Idiopathic thrombocytopenic purpura (ITP)
Immune Thrombocytopenic Purpura (ITP)
What is Immune Thrombocytopenic Purpura?
Immune thrombocytopenic purpura (ITP) is a platelet disorder in which the body produces antibodies that bind with platelets that are the small, sticky cells of the blood that help the blood clot. The platelet-antibody complex is then destroyed in the spleen or liver. This can occur as a short-term event or can be chronic. Patients who have low platelet counts are more likely to have bleeding with trauma or surgery. Some evidence suggests that ITP is related to an overactive immune system; however, the cause is not clearly understood. The condition happens more frequently following certain viral infections and certain immunizations. It also can be associated with autoimmune disorders such as lupus.
What are the symptoms of ITP?
Generally a child with ITP is otherwise healthy but has the sudden onset of bruises or small purple spots called petechiae on his/her skin. Spontaneous bleeding can occur in the mouth, nose, gastrointestinal tract or other areas. Bleeding can occur with injury and this can be especially dangerous if the bleeding occurs in the brain (called cerebral hemorrhage.)
How is ITP diagnosed?
There is no definitive, accurate test for ITP. The diagnosis of ITP involves assessing a medical history, physical examination and lab studies to be sure that the finding are consistent with ITP and that all other possible causes of the bleeding/bruising are ruled out.
In most cases, a blood test, including a complete blood count and smear for morphology, are performed. Other blood tests that may be considered include autoimmune studies, viral labs, liver and renal function tests. A bone marrow test may be performed if there is a question as to the diagnosis.
How is ITP treated?
In most cases, ITP in children resolves on its own. Your child's blood may be tested weekly or at longer intervals until the platelet count has returned to normal.
Treatment may be recommended based upon the platelet count, age of the patient, activity level and bleeding symptoms. When treatment is recommended, it may involve the following medications that help keep platelet counts at a safe level until your child's body recovers:
- Intravenous gamma globulin (IgG). This is a liquid concentrate of antibodies that is extracted from donated plasma and purified. This material blocks the spleen from removing the platelet-antibody complex. The response to IgG typically lasts 2-6 weeks and so treatment may have to be repeated. The infusion of IgG takes several hours and may be given in Children's infusion center. Possible side effects include nausea, vomiting, headaches, or fever. In rare cases, aseptic meningitis or kidney failure has occurred.
- Anti D immune globulin (WinRho). WinRho is a liquid concentrate of antibodies that target the Rh factor on red blood cells. The red blood cell antibody complex then is filtered through the spleen. This blocks the receptors that would normally trap the platelets in ITP. An infusion of WinRho requires less than 30 minutes to administer and can be given through the infusion center. The improvement lasts 2-6 weeks and so, like IgG, the treatment may have to be repeated if the child has continuing ITP. WinRho does not work in children with Rh-negative blood or those who have had their spleens removed. Possible side effects include fever, headaches, chills, nausea, vomiting, and anemia. In rare instances, kidney failure has occurred.
- Prednisone. Prednisone is a steroid which can increase platelet counts. Possible short-term side effects include irritability, stomach upset, sleep disturbances, increased appetite, weight gain, puffy cheeks, acne, frequent urination, sugar in the urine, and loss of bone density. When the medicine is stopped, the side effects will resolve. There can be serious long-term side effects to prednisone so typically treatment is given for just a few days or weeks at a time.
Other therapy may involve a splenectomy (removal of the spleen), Rituximab, or other immune suppression. These therapies are generally used in patients with chronic ITP.
What should parents do?
Be aware of medications that may increase bleeding. Parents should check with the hematology team before giving your child any medication other than acetaminophen (Tylenol.) Children experiencing low platelet counts should avoid the following medications:
- Aspirin or medicines containing aspirin. The medical name for aspirin that may appear on the label is acetylsalicylic acid.
- Anti-inflammatory medicines, such as ibuprofen or naproxen.
Keep your physician informed. If your child hits his/her head or has a serious accident, contact your hematologist immediately. Other signs or symptoms that should be noted and communicated to a physician include:
- Nosebleeds that last longer than 20 minutes
- Blood in the urine, stools, or vomit
- Blood during coughing
Be prepared to restrict activities when platelet counts are low. The hematology team will work with you to determine which sports and activities can continue and which pose a risk of bleeding that could be dangerous to a child with low platelet counts. Always make sure your child wears the appropriate safety equipment, such as helmets, kneepads, elbow pads, or wrist pads, during sports.
About treatment for ITP at Children's
Cancer and Blood Disorders program achieves outcomes that rank among the top national programs and cares for more than two-thirds of Minnesota children and adolescents with blood disorders. Care for ITP is provided through a division of the cancer and blood disorders program called the Center for Bleeding and Clotting Disorders. Through the center, families have access to the newest and most promising treatments and receive care spearheaded and coordinated by a board-certified hematologist/oncologist.
If you are a family member looking for a Children's hematologist or oncologist or wanting to schedule an appointment, please call our clinic at Children's – Minneapolis at (612) 813-5940.
If you are a health professional looking for consultation or referral information, please call Children's Physician Access at 1-866-755-2121 (toll-free) and ask for the on-call hematologist/oncologist.